function SetQueryFlag($flag_name, $flag_value)
{
$known_names = array("reverse_scan", "sort_method", "max_predicted_time", "boolean_simplify", "idf");
$flags = array("reverse_scan" => array(0, 1), "sort_method" => array("pq", "kbuffer"), "max_predicted_time" => array(0), "boolean_simplify" => array(true, false), "idf" => array("normalized", "plain"));
assert(isset($flag_name, $known_names));
assert(in_array($flag_value, $flags[$flag_name], true) || $flag_name == "max_predicted_time" && is_int($flag_value) && $flag_value >= 0);
if ($flag_name == "reverse_scan") {
$this->_query_flags = SetBit($this->_query_flags, 0, $flag_value == 1);
}
if ($flag_name == "sort_method") {
$this->_query_flags = SetBit($this->_query_flags, 1, $flag_value == "kbuffer");
}
if ($flag_name == "max_predicted_time") {
$this->_query_flags = SetBit($this->_query_flags, 2, $flag_value > 0);
$this->_predictedtime = (int) $flag_value;
}
if ($flag_name == "boolean_simplify") {
$this->_query_flags = SetBit($this->_query_flags, 3, $flag_value);
}
if ($flag_name == "idf") {
$this->_query_flags = SetBit($this->_query_flags, 4, $flag_value == "plain");
}
}
function ResetQueryFlag()
{
$this->_query_flags = SetBit(0, 6, true);
// default idf=tfidf_normalized
$this->_predictedtime = 0;
}